Organ key switch



April 9, 1-957 J. A. MATHEWS ETAL 2,788,400

ORGAN KEY SWITCH 2 Sheets-Shoot 1 Filed Jan. 13. 1955 wwmbw 1 i k n a kdw .w mf EEW l 215M Pmh a enrw M 4 0 aw? April 1957 v J. A. MATHEWS EIAL 2,788,400

ORGAN KEY SWITCH Filed Jan. 13, 1955 2 Sheets-Sheet 2 United States Patent M ORGAN KEY SWITCH Application January 13, 1955, Serial No. 481,524 6 Claims. (Cl. 20018) Norman B. Erickson,

This invention relates to electric switches for use primarily, but not necessarily, in the keying circuits of the electrical network of an electric organ, the same adapted to be actuated from the instruments keyboard for selective transmission of tone Signals to an electroacoustic translating system.

The invention is a further development of the switch mechanism disclosed in the Larsen et al. patent, No. 2,630,503, issued March 3, 1953.

The conventional keyboard of an organ comprises a plurality of chromatic octaves of playing-keys, such that for each octave there are seven white and five black keys, each mounted for pivotal motion about a horizontal axis. The keys of the conventional keyboard are sprung so that the pressure required to depress any individual key is usually from about two and a half to about three ounces.

An object of the herein disclosed invention is the provision of an electric switch assembly consisting of any desired number of individual switches, which assembly is adapted to be mounted in a fixed position at a suitable elevation beneath the back ends of the playing-keys and the individual switches connected to respective keys in a manner to (1) spring the keys; and (2) enable individual adjustment of each separate switch by a unique method to compensate for any variations that initially exist in the relationship of the electrically coactive elements when the assembly is mounted in its intended position to thereby insure uniformity in the circuit making and breaking operations of the switches in response to pivotal motion of their associated playing-keys, and, whereby, there is provided for each individual switch spring means functioning in a dual capacity to (a) spring an associated key to urge it to a playing position and (b) resiliently return the movable contactor of a respective switch to an olf condition when playing pressure is removed from the key.

Further objects of the invention are:

The provision of a switch assembly which may be economically manufactured and can comprise any desired number of sensibly identical, individually actuable switches adapted to be conveniently mounted as a unitary structure in operative relationship to a keyboard and the individual switches readily connected to respective playing-keys thereof.

The provision of a switch assembly, the coactive elements of each individual switch of which are structurally characterized by their sturdiness and ability satisfactorily to withstand the strains and stresses to which they are subjected and whereby, and due thereto, the individual switches will function with a high degree of uniformity and with full assurance that a keying circuit in which the switch is connected will be successfully opened and closed by pivotal motion of the key, first in one direction about its axis of rotation and then in an opposite direction as occurs when playing the key.

The provision of a switch assembly, the component parts of which may be easily and quickly fabricated into a compact, light-weight finished product.

2,788,400 Patented Apr. 9, 1957 Other objects will be manifest from the following description and accompanying drawings, in which:

Figure 1 is a view partly in elevation and partly in section of the switch organization showing same applied to a playingkey;

Figure 2 is a perspective view of the contactor mounting;

Figure 3 is a section taken on line 3-3 of Figure 2;

Figure 4 is a view in elevation of one of the contactors;

Figure 5 is a perspective view of the bus-bar mounting;

Figure 6 is a section taken on line 66 of Figure 5;

Figure 7 is a view in elevation of the switch assembly with one side of the housing removed and showing the switch actuators connected with respective playing-keys of a keyboard;

Figure 8 is a section taken on line 8-8 of Figure 7;

Figure 9 is a plan view of a portion of the playing-key showing the contactor adjusting means;

Figure 10 is a plan view on an enlarged scale of the adjusting nut for the resilient element of the contactor adjusting means;

Figure 11 is a perspective view of the resilient element of the contactor adjusting means; and

Figure 12 is a detailed end elevation of the casing structure.

At Figure l are shown two vertical flat strips or members 11 and 12 of hard dielectric material. These strips are arranged in parallel spaced apart relation and may be of any desired length, width and thickness. At 14 and 15 are similar upper and lower metallic members of thin gauge material.

The upper member 14 is formed at one of its long sides with a flange 16 which extends downwardly to overlap the outer face of strip 11, and, as shown, said member is formed with depending lugs 17 which engage the inner face of said member. The lower member 15 has one of its long sides similarly formed with a flange 13 which engages the outer face of member 11, and said member also has lugs 19 which engage the inner face of said member. Each of the members 14 and 15 is further provided with a longitudinal angular shoulder 20 against which the outer face of strip 12 bears and is retained by lugs 21 upon the respective members 14 and 15. The material of each of the members 14 and 15 extends in a horizontal plane from the angular shoulders 20 and has an angular flange 22 to which there is attached by fastenings 23 a metal closure plate 24. Thus there is formed a shell-like housing for the operating elements of the herein disclosed switch organization. To hold said strips 11 and 12 in their intended parallel spaced apart relationship, as partly provided for by the above constructional features, fastening bolts 25 connect the members 14 and 15 together to firmly clamp the strips 10 and 11 therebetween. The construction of said housing is such that its parts are separable and can be easily assembled in manufacturing the device and whereby the parts can be easily dissembled for access to parts within the housing as and when occasion therefor may arise.

At Figure 2 it is noted that strip 11 is rectangular and has adjacent to each of its ends a vertical row of equidistantly spaced apart horizontal holes 26, there being four such holes in the present embodiment of the invention. Intermediate of these rows of holes said member has longitudinally spaced apart vertical rows of equidistantly spaced apart eyelet holes 27. A hollow tubular eyelet 28 of thin gauge metal, such as brass, is fastened in each of said holes 27 by upsetting the metal of the tube at 29 and 30 against the inner and outer faces of said strip 11, the said eyelet being formed with diametrically opposite spaced apart integral jaw-like retainers 3131 between which is received the enlarged stub end 32 of a vertically resilient contactor C which preferably consists of closely wound springy wire formed with a long efifective contact portion of reduced diameter 32a which is a continuation of said enlarged stub. Said portion 32a extends through said eyelet and toward said closure plate 24. it is understood that the contactors C, common to any vertical row of eyelets 28, are sensibly identical and are vertically spaced apart from each other. Upon reference to Figure 2 it is seen that when the contactors are operatively mounted on strip 11, the reduced portions 32a thereof tend by their normal resiliency to extend in a plane perpendicular to the surface of said strip 11 and are in relative parallelism.

Strip 12 has at each of its ends a vertical row of equidistantly spaced apart holes 33 which are adapted for horizontal alignment with the holes 26 in said strip 11 when the two strips are clamped between the aforementioned housing members 14 and 15. The member 12 also has longitudinally spaced apart vertical rows of holes 34 adapted to be horizontally aligned with holes 27 in strip 11. Stated differently, there is a vertical row of holes 34 for and coactive with each vertical row of holes 27 in said strip 11. Extending longitudinally of member 12 at the outer face thereof are grounding bars 35 having right-angularly disposed end extensions 36 which pass through respective holes 33 in strip 12 and similarly through horizontally aligned holes 26 in said strip 11 when the two strips are operatively clamped between said members 14 and 15. The bars 35 are vertically spaced apart from each other and in fixed parallel relation to each other and close the outer face of strip 12 by eyelets 37 of substantially the same construction as the eyelets 28 upon strip 11. Similarly attached to the outer face of said strip 12 are bus-bars 38, such that there is one thereof for and electrically coactive with each of said grounding bars 35, the same disposed in uniform vertical spaced apart parallel relation thereto. These bus-bars are attached to said strip 12 by eyelets 39 which are the same in form and construction as the eyelets 2%. When the bus-bars 33 and the grounding bars 35 are mounted on said member in the manner just stated, an excellent electrical connection is made between the same and their supporting eyelets 28 and 39. We make no claim to the form, construction and design of the eyelets apart from the specific environment in which they are used.

Upon referring to Figure 7 of the drawings, it is noted that the vertical rows of holes 34 in member 12 are arranged so that there is one such hole in the space between a respective bus-bar 38 and a correlated grounding bar 35, also that the long portion 32:: of a respective contactor C passes through a respective hole 34 to dispose said portion in coactive relationship to a respective bus-bar and a correlated grounding bar to respectively engage and disengage same in response to vertical motion of said portion, it being understood that the external diameter of the portion 32a is less than the vertical distance between grounding bar 35 and its correlated bus-bar 38. For each vertical row of holes 34 is a corresponding number of said contactors C whose long portions 320 project through respective ones of said holes. For each vertical row of said contactors, there is a playing-key-actuated element 4% comprising a thin flat strip of nylon or equivalent tough and somewhat flexible dielectric material of suitable thickness, the same having upper and lower branches 41 and 42 and intermediate horizontally aligned lugs KL-43. Vertically spaced apart holes 44 are formed in the lower branch 42 through which the long portions 32a of contactors C extend. In each of the lugs 4l3-- 43 is a hole 45, and at the upper end of the branch 41 is a hole 46. For each of said elements and formed in said member 15 is a pair of longitudinally spaced apart holes 4747, and passing upwardly therethrough are coiled retractile springs 4848 whose upper ends are connected in said holes and whose lower ends are formed into enlarged stubs 47a to engage against the bottom face of member 15 and prevent the springs from pulling through the holes when the springs are connected to said lugs li-43. The arrangement is such that each element is resiliently urged in a downward direction to cause all contactors which are common to said element to engage respective grounding bars 35.

The invention may comprise any number of vertical rows of resilient contactors C, each row consisting of any desired number of individual contactors. When the invention is used in the electrical network of a keyboard musical instrument for selectively transmitting audio tone signals to an electroacoustic translating system, the elements at} will be equidistantly spaced apart from each other, the spacing being with regard to the sequential order .of the keys K of the instruments keyboard, such that there will be one such element for and actuable by the key to transmit vertical motion thereto in one direction. T he back end of each playing-key has a vertical hole 5t) therein through which the upper end of a respective element t) extends, said end of the key has supported thereby a vertically adjustable metallic element 51 which passes through the hole 46 in the upper end 41 of said element 4%. Said element 51 comprises and 'a straight length wire of suitable gauge formed at one end with a closed loop 52 through which a vertical threaded stub 52 on the key extends, and, as shown at Figure l and 3, said stub is provided with an adjusting nut 53 provided with a circular series of radial notches 54. The opposite end of said element 51 is bent downwardly at 51a and is freely received in a recess 56 in the upper face of the back end of said playing-key.

When the invention is fixedly mounted and arranged as shown at Figure 7, the upper ends of the actuating elements 4% are hung, so to speak, from the vertically adjustable elements 51, the aforementioned retractile springs 48-48 for each of said elements 49 functioning to urge said elements in downward directions, moving the playing-keys about their axes so that the front ends of the keys are raised to playing positions. The dual purpose of the springs and their connection with said elements 45) is an important feature of the invention in that it is not necessary separately to spring the keys, as heretofore has been the common practice. Downward movement of said elements it) under the normal urge of said springs 4d flexes the contactors C with resultant effective electrical engagement thereof with their respective grounding bars 35. When playing pressure is applied to the front end of a respective playing-key, the back end of the key tilts in an upward direction, and element 4 which is associated with or hung from the key is moved in an upward direction, thereby flexing the contactor in a reverse direction to move it oil of said grounding bar and into effective electrical engagement with the bus-bar 38 that immediately overlies same.

Adjustment or" the nuts 53 tilts the elements 51 from which elements 4i; are hung, thereby varying the tension of springs 48 and Val ing the -Jatiozudp of the contactors to their correlated bus-bars 3% and grounding bars 35'. in this manner, the time required for the contactors to make and break the circuits in which they are connected can be controlled to a nicety when playing said keys K. This feature of the invention also important in that the white and black of an organ have respective fulcrum points which determine the levera action of the keys, requiring that there shall he me to pensate for any variable in the relationship of 1c co v elements to insure uniformity of cper ion of each individual contactor C. When the invention is applied to a keyboard, the tension of springs ill--48 is controlled by manually adjusting the nuts 53, thereby either raising or lowering said elements 4t. By this procedure, the contactors C are initially adjusted relative to their meeting bus and grounding bars 3-5 and 33 to insure that the time to make and break a respective circuit is the same both for the short black keys andthe longer white ke'ysi- While we prefer to use sensibly identical, closely coiled springs as the herein disclosed resilient contactors, which in certain respects are like the contactors shown in the patent to Larsen et al., No. 2,630,503, straight length, cross-scctionally circular Phosphor bronze or well known equivalent springy material may be substituted therefor with good results. However, stress is placed upon the forms, shapes and general design of said contactors C, enabling use thereof with certain unique features of the herein disclosed invention, and particularly the facility with which they may be arranged with oth elements to produce a simple composite organization of elements by a simplified manufacturing process.

It is an important feature of our invention to provide for good rubbing action of the contactors with their coacting bus and grounding bars and to insure to practical degree clean surfaces of both the contactors and said bus and grounding bars to thereby establish good electrical conductivity at the effective points of contact of these elements.

As the gist of the invention is an organization of elements for making and breaking an electrical circuit in response to pivotal motion of a playin -key first in one direction and then another and for utilizing the energy of a spring to (a) spring the key; (b) disengage a movable contactor from a fixed contact element under the normal urge of the spring; and (6) enable manual adjustment of the contactor for intended coaction thereof with said fixed contact elements, it is within the spirit and intention of the instant invention to substitute for said bus-bar and said grounding bar a fixed element only and a coacting movable contact, the latter of any well known construction adapted for actuation by said motion transferring element 49.

The term bus-bar as used herein shall therefore mean any fixed contact element or conductive element and the term resilient contactor shall be construed to mean any well known contactor capable of motion to and from a fixed contact element. and adapted to be operated in response to a motion imparting means to function in the manner described.

The term elongated key as used herein shall mean a key of the type employed in the conventional keyboard of an organ, a piano or similar keyboard musical instruments. In such instruments the white keys are longer than the black keys. These white and black keys are mounted to pivot on vertical pins of the fulcrum bar which forms part of the key bed, the pins being differently related to each other and with regard to the respective lengths of the keys so that when the keys are sprung, each may be depressed by application thereto of the same amount of playing pressure. in the instant embodiment of the invention. vertical motion of the White keys is limited by stop S which would be disposed at the front of the case of the instrument. This stop is adapted to engage 2. lug L at the front end of the key. Movement of the black keys is limited in an upward direction by a stop S. Downward motion of the white and black keys is limited by similar felt strips S".

What we claim as our invention is:

l. The combination comprising a substantially horizontally disposed keyboard, the playing-keys of which are elongated and mounted between their front and back ends for pivotal motion in a vertical plane, the back ends of said keys each having a vertical hole extending therethrough; a unitary organization of. electric switches including a switch for and actuable by each individual one of said keys, said organization adapted to be mounted a desired distance beneath the back ends of said keys and said switches each having an actuating element for open and close-circuiting the switches in response to pivotal motion of the keys first in one direction and then in an opposite direction, and said elements having upper end portions extending through the openings in the back ends of respective ones of said keys; means for freely suspending each of said elements from the back end of its respective key, and spring means for and coactive with each of said elements tending always to exert a downward pull upon the element with resultant opencircuiting of a respective switch of said organization of switches and so that the front end of the key common to said element is raised for application of pressure thereon to move said element in an upward direction against the urge of spring with resultant close-circuiting of said switch.

2. The combination according to claim 1 wherein the suspending means for each of said elements is adjustable for varying the tension of its coactive spring.

3. The combination comprising, a substantially horizontally disposed keyboard, the playing-keys of which are elongated and mounted between their front and back ends for pivotal motion in a vertical plane, the back end of each key having a vertical hole extending therethrough; an electric switch for and actuable by each separate key during pivotal motion of the key first in one direction and then in an opposite direction and disposed beneath the back end thereof and provided with a vertically movable actuating element for open-circuiting the switch on downward motion of the element and closecircuiting same on upward motion of said element, said element having an upper end portion extending through the vertical hole in the back end of a respective key; means for freely suspending said element from its upper end at said back end of the key; and spring means for and coactive with each one of said elements for resiliently urging same in a downward direction to open circuit the switch and tilt a respective key to raise the front end thereof.

4. The combination according to claim 3, wherein means are provided at the back end of each key which is coactive with the element suspending means for manually adjusting the element to vary the tension of a respective spring.

5. The combination according to claim 3, wherein the element suspending means for the switch of each key comprises a substantially straight length of metal extending lengthwise of and disposed above the back end of the key and freely passing horizontally through the upper end of said element and having one of its ends freely engaging the key forwardly of the upper end of said element and its opposite end mounted on the key rearwardly of the upper end of said element for vertical adjustment of said element.

6. The combination comprising an elon ated and substantially horizontally disposed playing-key supported between its front and back ends for pivotal motion about a horizontal axis, said key having therein, at its rear end, a hole extending vertically therethrough; a vertically movable element having its upper end passing through said hole; means on the back end of the key for manually adjusting the element vertically; an electric switch coactive with the element; and spring means tending always to pull the element in a downward direction and tilt the key to raise the front end thereof with resultant downward motion of the element to open circuit said switch.

References Cited in the file of this patent UNlTED STATES PATENTS 

